This website contains problems from math contests. Problems and corresponding tags were obtained from the Art of Problem Solving website.

Tags were heavily modified to better represent problems.

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Found problems: 2

1977 Chisinau City MO, 146
Prove that $n$ ($\ge 4$) points of the plane are vertices of a convex $n$-gon if and only if any $4$ of them are vertices of a convex quadrilateral.
convex polygon non-convex convex geometry polygon polygons

2006 Tournament of Towns, 5
A square is dissected into $n$ congruent non-convex polygons whose sides are parallel to the sides of the square, and no two of these polygons are parallel translates of each other. What is the maximum value of $n$? (4)
non-convex max polygon combinatorics combinatorial geometry geometry inequalities number theory polygons